Off-highway vehicles (“OHVs”), such as, for example, mining vehicles used to haul heavy payloads excavated from open pit mines, usually employ motorized wheels for propelling or retarding the vehicle in an energy efficient manner. This efficiency is typically accomplished by employing a large horsepower diesel engine in conjunction with an alternator, a main traction inverter, and a pair of wheel drive assemblies housed within the rear tires of the vehicle. The diesel engine is directly associated with the alternator such that the diesel engine drives the alternator. The alternator, in turn, powers the main traction inverter, which supplies electrical power having a controlled voltage and frequency to electric drive motors of the two wheel drive assemblies. Each wheel drive assembly houses a planetary gear transmission that converts the rotation of the associated drive motor energy into a high torque, low speed rotational energy output which is supplied to the rear wheels.
Planetary gear transmissions are generally operated in a wet lubricated condition. As will be appreciated, it is desirable to minimize or prevent leakage of lubricants, e.g., oil, from wheel drive assemblies as such leakage leads to vehicle downtime for disassembly, inspection, and repair. In particular, in OHV wheel drive assemblies that include a rotary torque tube overlying a wheel frame, an oil seal ring may be fastened to the wheel frame so that it engages a complementary seal body mounted on the torque tube. Although the oil seal ring and body form an effective labyrinth seal, operating deflections of the torque tube and of the seal body can produce rubbing wear between the ring and the body such that the sealing function could potentially deteriorate over time.
Further, seal bodies are weight-controlled, which is often accomplished by limiting their axial thickness. Additionally, to avoid the weight of bolted flanges, the body may be interference fit on the torque tube. In designs where the seal body is relatively axially thin, however, an interference fit may cause a “cupping” or “coining” deflection of the body toward the seal ring, which potentially exacerbates rubbing wear.
Accordingly, it is desirable to provide a seal body that provides a durable and reliable seal without being of excessive weight or thickness.